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KVM: ppc: Write only modified shadow entries into the TLB on exit

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Track which TLB entries need to be written, instead of overwriting everything
below the high water mark. Typically only a single guest TLB entry will be
modified in a single exit.

Guest boot time performance improvement: about 15%.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Hollis Blanchard
2008-07-25 13:54:52 -05:00
committed by Avi Kivity
parent 20754c2495
commit 83aae4a809
6 changed files with 66 additions and 20 deletions
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15
arch/powerpc/kvm/powerpc.c
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@ -27,6 +27,7 @@
#include <asm/cputable.h>
#include <asm/uaccess.h>
#include <asm/kvm_ppc.h>
#include <asm/tlbflush.h>
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
@ -307,14 +308,28 @@ static void kvmppc_load_guest_debug_registers(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
int i;
if (vcpu->guest_debug.enabled)
kvmppc_load_guest_debug_registers(vcpu);
/* Mark every guest entry in the shadow TLB entry modified, so that they
* will all be reloaded on the next vcpu run (instead of being
* demand-faulted). */
for (i = 0; i <= tlb_44x_hwater; i++)
kvmppc_tlbe_set_modified(vcpu, i);
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
if (vcpu->guest_debug.enabled)
kvmppc_restore_host_debug_state(vcpu);
/* Don't leave guest TLB entries resident when being de-scheduled. */
/* XXX It would be nice to differentiate between heavyweight exit and
* sched_out here, since we could avoid the TLB flush for heavyweight
* exits. */
_tlbia();
}
int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,